This application claims priority to Netherlands Patent Application No. 1017811, filed on Apr. 10, 2001.
The invention relates to a hand luggage locker assembly for use in an aircraft cabin, comprising a shell-like locker, a track mechanism for moveably connecting said locker to an aircraft structure between a closed position and an open position, a lifting mechanism for relieving muscle power required for a user to move said locker between said closed position and said open position, said lifting mechanism comprising a moveable lifting body which, on one side, is connected to said track mechanism or to said locker and, on its other side, is connected to said aircraft structure, which lifting body is coupled to a pneumatic system.
In large passenger aircraft which are to be constructed in future, the hand luggage lockers will be so high that it will not be easy to put hand luggage into them or to remove hand luggage therefrom. It is already known to mount hand luggage lockers moveably on the aircraft structure in such a manner that the lockers can move approximately half a meter up and down. In a lowermost position, it is then easy to introduce or remove hand luggage, after which the locker can be moved back upwards to an uppermost position. Not every passenger is tall or strong enough to move the locker all the way back up on his own. This is because the locker together with hand luggage may weigh about 50 kg. With this in mind, it is already known to provide a lifting mechanism which is either completely responsible for or considerably facilitates moving the locker up and down. Lifting mechanisms which have already been used for this purpose employ electric motors or air springs. However, electric motors may cause electrical accidents, such as short circuits, overloads and fires. In the uppermost position of the locker, air springs take up large amounts of space and cannot automatically be adapted to variations in the load weight.
U.S. Pat. No. 5,441,218 has disclosed another variant of a lifting mechanism for a hand luggage locker assembly, in which the lifting mechanism comprises piston-cylinder devices which form part of a pneumatic system which is supplied with compressed air. The compressed air in this case originates from pressure compressors. The lifting mechanism can be actuated by means of an on/off switch provided at the corresponding locker. In addition, the assembly comprises a control unit for controlling electrically actuable safety valves. The control unit will have to react automatically as a function of signals emitted by pressure sensors at the edges of the locker and will have to stop the upward or downward movement of the locker quickly, for example in the event of body parts or luggage becoming jammed during a movement of the locker.
A drawback of the lifting mechanism which is known from U.S. Pat. No. 5,441,218 is that it takes up large amounts of space, is expensive to produce and is heavy. In view of the high pressures used, of up to more than 7 bar, for the compressed air in the pneumatic system, in the event of a failure in the pneumatic system, the system may rapidly lead to excess noise and very dangerous situations, such as hoses flapping around. The high weight is very disadvantageous in the aircraft industry in view of the correspondingly increased fuel consumption during flying. A further drawback is that, in the event of a defect in the compressed-air system, the locker cannot be moved up and down by more than a few centimeters.
It is an object of the present invention to overcome the above mentioned drawbacks and to provide a user-friendly and safe hand luggage locker assembly. In particular, it is an object of the invention to provide a lifting mechanism for an assembly of this type which takes up little space and provides considerable flexibility.
According to the invention, this object is achieved by a hand luggage locker assembly for use in an aircraft cabin, comprising a shell-like locker, a track mechanism for moveably connecting said locker to an aircraft structure between a closed position and an open position, a lifting mechanism for relieving muscle power required for a user to move said locker between said closed position and said open position; said lifting mechanism comprising a moveable lifting body which, on one side, is connected to said track mechanism or to said locker and, on its other side, is connected to said aircraft structure, which lifting body is coupled to a pneumatic system, wherein said pneumatic system comprises means for supplying an underpressure compared to an ambient pressure in said cabin, control means being provided for at least supplying said underpressure to said lifting body when said locker is to be moved upwards in a controlled manner with the aid of said underpressure as power source. The pneumatic system comprises means for supplying a reduced pressure compared to the pressure prevailing in the aircraft cabin. There are control means for at least supplying such an underpressure to the lifting body when the locker is to be moved upwards. Underpressure has a very low specific energy density, which results in considerable safety. Electrical systems can be omitted, which is also of benefit to safety. When using underpressure, it is advantageously possible to utilize underpressure pumps which are already present in an aircraft, for example for extraction from the toilets. During flying, it is even possible to make use of pressure differences which prevail between the inside and outside of the aircraft. The pneumatic system with underpressure means may advantageously also fulfil a role in the general treatment of the air. Should the underpressure fail, the locker can still always be moved up and down fully by hand. Consequently, underpressure as a power source is a very advantageous means of at least partially relieving the load on a user when moving a hand luggage locker up and down.
On the ground, both the pressure outside the aircraft and the pressure in the aircraft cabin are approx. 1 bar. At a high cruising altitude, the pressure outside the aircraft drops considerably. For example, at a height of 3 km, the pressure is approx. 0.75 bar, and at 8 km the pressure is approx. 0.25 bar. The cabin pressure may also fall to some extent, but is maintained at, for example, approx. 0.75 bar. Taking this into account, the underpressure means are advantageously designed in such a manner that they supply a substantially constant, desired pressure difference with respect to the pressure prevailing in the cabin at any specific time. In practice, it has been found that the pressure difference between the cabin pressure and the underpressure which is to be supplied by the underpressure means preferably lies in the range between 0.2-0.5 bar.
The dimensions of the lifting body may be such that the underpressure is able to move the locker upwards without further external influence. Preferably, however, the unit is designed in such a manner that it serves as a lifting energizer, considerably relieving the load on a user when the user is pressing the locker upwards. In this case, the lifting energizer is preferably designed in such a way that the muscle force which is still required has to be exerted over the entire distance during the upwards movement and is substantially constant. An advantage of such a lifting energizer of this nature is that the user feels a resistance, which is expected, but a less heavy resistance.
Further preferred embodiments are defined in the subclaims.